package com.xtaller.lazy.lib.kit;


import com.xtaller.lazy.lib.convert.S;
import lombok.var;
import org.apache.commons.lang3.StringUtils;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

/**
 * @version V1.0
 * @author: Taller
 * @date: 2019-04-02
 * @Description: 全局id
 */
public class IdUtil {
    private long workerId;
    private long datacenterId;
    private long sequence = 0L;
    private long twepoch = 1520089500000L;                              //  Thu, 04 Nov 2010 01:42:54 GMT
    private long workerIdBits = 5L;                                     //  节点ID长度
    private long datacenterIdBits = 5L;                                 //  数据中心ID长度
    private long maxWorkerId = -1L ^ (-1L << workerIdBits);             //  最大支持机器节点数0~31，一共32个
    private long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);     //  最大支持数据中心节点数0~31，一共32个
    private long sequenceBits = 12L;                                    //  序列号12位
    private long workerIdShift = sequenceBits;                          //  机器节点左移12位
    private long datacenterIdShift = sequenceBits + workerIdBits;       //  数据中心节点左移17位
    private long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits; //  时间毫秒数左移22位
    private long sequenceMask = -1L ^ (-1L << sequenceBits);                          //  4095
    private long lastTimestamp = -1L;

    private static class IdGenHolder {
        private static final IdUtil instance = new IdUtil();
    }

    public static IdUtil get(){
        return IdGenHolder.instance;
    }

    public IdUtil() {
        this((int)(1+Math.random()*(10)), (int)(1+Math.random()*(10-1+1)));
    }

    public IdUtil(long workerId, long datacenterId) {
        if (workerId > maxWorkerId || workerId < 0) {
            throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0", maxWorkerId));
        }
        if (datacenterId > maxDatacenterId || datacenterId < 0) {
            throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0", maxDatacenterId));
        }
        this.workerId = workerId;
        this.datacenterId = datacenterId;
    }

    public synchronized long nextId() {
        //获取当前毫秒数
        long timestamp = timeGen();
        //如果服务器时间有问题(时钟后退) 报错。
        if (timestamp < lastTimestamp) {
            throw new RuntimeException(String.format(
                    "Clock moved backwards.  Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));
        }
        //如果上次生成时间和当前时间相同,在同一毫秒内
        if (lastTimestamp == timestamp) {
            //sequence自增，因为sequence只有12bit，所以和sequenceMask相与一下，去掉高位
            sequence = (sequence + 1) & sequenceMask;
            //判断是否溢出,也就是每毫秒内超过4095，当为4096时，与sequenceMask相与，sequence就等于0
            if (sequence == 0) {
                //自旋等待到下一毫秒
                timestamp = tilNextMillis(lastTimestamp);
            }
        } else {
            //如果和上次生成时间不同,重置sequence，就是下一毫秒开始，sequence计数重新从0开始累加
            sequence = 0L;
        }
        lastTimestamp = timestamp;
        // 最后按照规则拼出ID。
        // 000000000000000000000000000000000000000000  00000            00000       000000000000
        // time                                       datacenterId   workerId    sequence
        return ((timestamp - twepoch) << timestampLeftShift) | (datacenterId << datacenterIdShift)
                | (workerId << workerIdShift) | sequence;
    }

    protected long tilNextMillis(long lastTimestamp) {
        long timestamp = timeGen();
        while (timestamp <= lastTimestamp) {
            timestamp = timeGen();
        }
        return timestamp;
    }

    protected long timeGen() {
        return System.currentTimeMillis();
    }

    public static Long getLongId(int businessId) {
        String id = get().nextId() + "";
        id = id.substring(8, 18);
        String ymdh = TimeUtil.formatDate("yyMMdd");
        return Long.parseLong(S.apppend(businessId + ymdh + id));
    }
    public static void main(String[] args){
        List<Long> list = new ArrayList<>();
        for(int i=0;i<9;i++){
            long tem = getLongId(100);
            System.out.println(tem);
            list.add(tem);
        }
        long temp = 0L;
        for (int i = 0; i < list.size() - 1; i++)
        {
            temp = list.get(i);
            for (int j = i + 1; j < list.size(); j++)
            {
                if (temp == list.get(j).longValue())
                {
                    System.out.println("第" + (i + 1) + "个跟第" + (j + 1) + "个重复，值是：" + temp);
                }
            }
        }
    }

}
